Staying up late, sleeping in every day and eating after 8:00 pm may be risk factors in weight gain. A recent study from Northwestern Medicine found that late sleepers consumed 248 more calories a day, mainly at dinner and later in the evening. They ate half as many fruits and vegetables, twice the fast food and drank more full-calorie sodas than those with earlier sleep times.
"The extra daily calories can mean a significant amount of weight gain - two pounds per month - if they are not balanced by more exercise," said co-lead author Kelly Glazer Baron, a health psychologist and a neurology instructor at Northwestern University Feinberg School of Medicine.
The study followed 51 participants, 23 late sleepers and 28 normal sleepers, with an average age of 30 for a week. The participants wore a wrist actigraph to calculate their sleep and activity levels and completed food consumption diaries.
Late sleepers went to sleep at an average time of 3:45 am and woke up by 10:45 am, ate breakfast at noon, lunch at 2:30 pm, dinner at 8:15 pm and a final meal at 10:00 pm. Normal sleepers on average were up by 8:00 am, ate breakfast by 9:00 am, lunch at 1:00 pm, dinner at 7:00 pm, a last snack at 8:30 pm and were asleep by 12:30 am.
The study showed that in addition to the number of calories consumed each day, the timing was important. Those who ate after 8:00 pm were more likely to have a higher BMI, even after controlling for sleep timing and duration.
“The research findings could be relevant to people who are not very successful in losing weight,” said Phyllis Zee, M.D., the study’s lead author. "The study suggests regulating the timing of eating and sleep could improve the effectiveness of weight management programs."